I. Field
The following description relates generally to wireless communications and more particularly to estimating frequency error.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content, such as voice, data, and so forth. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, and so on). Examples, of multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems, orthogonal frequency division multiple access (OFDMA) systems, and others.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations through transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication from the base stations to the terminals and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. The communication link can be established through a single-in-single-out (SISO), multiple-in-single-out (MISO), or a multiple-in-multiple-out (MIMO) system.
Generally, to estimate a frequency error at least two consecutive training sequences (e.g. pilot symbols) are utilized. However, some systems only provide a single training sequence and/or more than one training sequence, each appearing in a different frequency area. Frequency error estimation cannot be reliably estimated in systems that do not provide two consecutive training sequences occupying the same bandwidth.